The present invention relates to processes for the production of a poly(ester-carbonate), and especially to such processes wherein phenolphthalein is one of the aromatic dihydroxy compounds used, and in which the aromatic dihydroxy compounds are introduced as alkaline metal or alkali earth metals salt (that is, interfacial processes).
A poly(ester-carbonate) having carbonate moieties, terephthalate moieties and moieties derived from bisphenol-A are described in U.S. Pat. No. 4,156,069 to Prevorsek et al (1979). The process employed in that reference was a solution process, introducing the bisphenol in its neutral form, and employing a catalyst-acid acceptor to neutralize by-product hydrogen halide. A modification of that poly(ester-carbonate), having as the aromatic dihydroxy moiety a moiety derived from phenolphthalein, either instead of or in addition to the bisphenol-A moiety, is described in U.S. Pat. No. 4,310,652 to DeBona et al (1982). The primary synthetic procedure disclosed in U.S. Pat. No. 4,310,652 is also a solution process, but there is some general description that the polymer disclosed can be produced by interfacial processes or by hybrid solution-interfacial processes. See especially Col. 4, lines 54-59; Col. 5, lines 1-6; and Col. 6, lines 24-31 and 38-43.
An interfacial process for the production of the poly(ester-carbonate) of U.S. Pat. No. 4,156,069, and other materials, are described in U.S. Pat. No. 4,255,556 to Segal et al (1981). In that process, at least a portion of the phosgene is reacted with the bisphenolate (e.g. aqueous disodium bisphenol-A) before or during reaction of acid chloride (e.g. terephthaloyl chloride) with bisphenolate. As described more fully below, the application of the process of U.S. Pat. No. 4,255,556 to the production of the phenolphthalein-containing polymer of U.S. Pat. No. 4,310,652 has met with only limited success. It is accordingly an object of the present invention to produce a phenolphthalein-containing poly(ester-carbonate) by interfacial techniques with desired polymer characteristics, and especially with reasonably high solution viscosities and reasonably low color.
Other interfacial processes for producing various poly(ester-carbonate) polymers are disclosed in U.S. Pat. Nos. 4,252,939 to Mori et al. (1981); 4,260,731 to Mori et al. (1981); 4,278,787 to Swart et al. (1981); 4,238,597 to Markezich et al. (1980); and 4,238,596 to Quinn (1980). In addition, polycarbonates containing phenolphthalein, and polyesters including phenolphthalein are known, as indicated in the literature cited in the second paragraph of U.S. Pat. No. 4,310,652, and especially British Pat. No. 1,179,400 (Jan. 28, 1970) and U.S. Pat. No. 3,523,078 (Aug. 4, 1970) of V. V. Korshak et al.